将索引添加到BufferGeometry不起作用？

我一直试图使用THREE.BufferGeometry()绘制一个非常基本的矩形.这是代码 -

var geometry = new THREE.BufferGeometry();
var material = new THREE.MeshBasicMaterial({color: 'rgb(255, 0, 0)'});


var verticesArray = [20, 0, 0, 0, 20, 0, -20, 0, 0, 0, -20, 0];
var vertices = new Float32Array(verticesArray, 0, 12);

var indicesArray = [0, 1, 2, 0, 2, 3];
var indices = new Uint16Array(indicesArray, 0, 6);

geometry.addAttribute('position', new THREE.BufferAttribute(vertices, 3));
//geometry.addAttribute('index', new THREE.BufferAttribute(indices, 3));
geometry.setIndex(new THREE.BufferAttribute(indices, 3));


var mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);

不幸的是它不起作用.它也没有抛出任何异常.据我所知,我做的一切都是正确的.我有四个顶点,我以逆时针顺序描述了两组索引.

有谁能告诉我这里可能出现什么问题？

它应该是 geometry.setIndex(new THREE.BufferAttribute(indices, 1));